As network bandwidth has increased over the years, multimedia technology has made it possible to broadcast multimedia programs and content comprising multiple corresponding media streams, such as a webcast, over the Internet to user devices for viewing. Multimedia technology has further enabled transmitting each of the media streams from different sources through different Internet pathways to the user devices. For example, the multimedia content may be an online video presentation, comprised of a live video image of a presenter streamed over an Internet pathway to viewer/player devices. The content may also comprise a corresponding sequence of presentation slides being discussed by the speaker, which is streamed from a separate device over a separate network pathway to the user devices. However, due to differing latencies, encoding and transcoding times, network and local buffering, and other such delays in the different Internet pathways, the receipt of the media stream and the presentation slides through different pathways are typically out of synchronization when they arrive at a viewing device. For example, the playback of the streamed live video over the first network pathway may be received seconds or even minutes behind the sequence of presentation slides received over the other network pathway. Such time discrepancies between receipt of the corresponding media streams may also vary among the different user devices receiving the media streams. Because the streamed media and the on-screen events that are intended to be viewed in synchronization with the streamed media may arrive at the viewer's computer at different times because of these varying and unpredictable delays, combining them into a unified viewing experience without re-synchronization risks an incoherent viewing experience.